Why Democrats/Progressives Want to Destroy the Middle Class

I've often wondered why Leftist Democrats and Progressives hate the middle class so much.  Why do they have so much envy and work like demons, night and day, to undermine, demoralize, and destroy the backbone of this country.

My primary theory was they had a rich neighbor that made them feel bad or they grew up in a broken home, poor and wanting to destroy those they always perceived as being "better" than them.  To bring the "rich" down to their own level so to speak.

I recently read a great article in WSJ entitled "The Soccer Mom Revolt Against Common Core" that changed my mind to their motivation.

In the last paragraph of the article, discussing the Obama administration's troubles implementing Common Core, it states exactly what drives the enduring hate:

Prof. Greene thinks the administration’s education agenda has crossed the wrong voters. “They’re going to lose,” he said, citing White House hubris and overreach. “You can’t beat organized upper-middle-class people. They will fight back and you will lose.”

The Democrats and Progressives are always and forever about gaining power.  The upper middle class is one of the few bastions of power left that can stand up to them and thwart their final takeover of the culture.  For this, they must be destroyed, because nothing must come between a Leftist and power.